Variable load brake for railway cars



Jui!! 12, 1949 v A. G. H. CARLBOM 2,475,81@

` VARIABLE LOAD BRAKE FOR RAILWAY CARS Filed April :50, 1946 2sheets-sheet 2 Patented July 12, 1949 VARIABLE LOAD BRAKE FOR RAILWAYCARS Axel Georg Hjalmar Carlbom, Malmo, Sweden,

assignor to Svenska Aktiebolaget Bromsregulator, Malmo, Sweden, acorporation of Sweden Application April 30, 1946, Serial No. .666,071

9 Claims. 1

This invention relates to railway car brakes and more particularly tovariable load brakes in railway cars, especially freight cars, of thetype comprising a car body and two swivelling trucks carrying andguiding the car body at the two ends thereof.

The chief object of the invention is to provide an improved car truckbrake comprising a brake rigging including a load-controlled variableleverage Y gear for adjusting the brake applying leverage rautomaticallyaccordingr t0 the load of the truck. y

A further object of the inventionis to provide an improved variableloadbrake of the loadcontrolled variable leverage type in a car truck ofthe conventional type comprising a wheeled frame having Vtwo sidemembers, and a crossbeam orbolster carriedvby and guided in the sidemembers of the frame and supported therefrom by springs.

A further object of the invention is to provide a truck brake comprisinga brake rigging including a load-controlled variable leverage geardisposed and housed in the spring-supported bolster of the truck,whereby-the bolster and the variable leverage gear may be mounted as aconstructional unit on the truck frame.

A further object of the invention is to provide such a mechanism for theload-control of the variable leverage gear as will make this controlindependent of nonuniform distribution of the load of the truck onthewheels at the two sides of the truck.

A further object of the invention is to provide a truck brake comprisinga brake rigging including a variable leverage gear, and mechanism forautomatically controlling said gear according to the load of the truck,in which said gear and said mechanism are disposed and housed in thespring-supported bolster of the truck, whereby the bolster and said gearand control mechanism may be mounted as a constructional unit on thetruck frame.

For these andv such further objects as may become apparent from thefollowing description in which reference is hadto the accompanyingdrawings forming part of this specication, the invention consists in theconstruction, combination and organization of parts hereinafterdescribed and illustrated by way of examples on the drawings and finallypointed out in the appendant claims. Y Y

In the drawings:

Fig. 1 is a longitudinal vertical section of a car (Cl. 18S- 195) truckequipped with my improved variable load brake.

Fig. 2 is a plan view, partly in section, of the truck and the brakeequipment thereon, and

Fig. 3 is a transverse vertical section substantially onthe line III-IIIin Fig. 2, whereas Fig. 4 is a detail plan view, partly in section,illustrating a modification.

The truck shown in the drawings is of the conventional type comprising aframe with two wheel pairs I and 2 having their axles 3 and ll,respectively, journalled in twoside members 5 and 6 of the frame, and acrossbeam or bolster carried by and guided in theside members 5 and 6and supported therefrom'by springs 3 and 9, respectively'.

Disposed in a housing IIJ provided in, and preferably made integralwith, the hollow bolster I is a variable leverage gear forming part ofthe brake rigging of the truck and comprising a lever II and a shiftablefulcrum I2 therefor. When braking, the brake power 'is transmitted toone end I3 of the lever II, which for this purpose may be connected to abrake pull rod YI!! (Fig. 2) which may be one of two main brake pullrods extending from a couple of equalizing brake levers associated witha brake cylinder mounted on the car body (not shown) which vtheswivelling truck is to carry (compare my U. S. application Ser. No.666,070 filed April 30, 1946, now Patent Number 2,432,467, datedDecember 9, 1947.

It is also possible to use a separate brake cylinder on each truck. Inthis case, as shoWn lin Fig. 4, the brake cylinder I5 preferably may beattached to a removable cover I6 closing an opening to the interior ofthe housing I at one side of the spring-supported crossbeam or bolster''1, the end I3 of the lever II being connected to the push rod I 'I ofthe brake cylinder, which push rod projects into the housing I0 throughan opening I8' in the cover I6.

Preferably the end I3 of the lever II is guided in its movement by beingconnected to an arm I9 pivoted at 20 to the housing ID (compare the U.S. Patent No. 2,204,925). Further the lever II may be provided with aroller 2| or the like coacting with a hook-shaped guiding member 22 in amanner and for purposes explained in the U. S. Patent No. 2,384,257. Inthe constructionalv forms shownv in Figs. 2 and 4 the said guidingmember 22 is mounted on the cover I6. ,The shiftable fulcrum I2 ismovable along a track 23 formed inthe housing I0 and extendinglongitudinally of the bolster 1, and may be guided in its movement bysuitable guiding means (not shown) preferably constructed as a laminatedbrake for arresting the shiftable fulcrum in its position when subjectedto pressure from the lever Il during braking as disclosed in the U. S.Patent application Ser. No. 595,468 to Bert Henry Browall, led May 23,1945, now Patent Number 2,427,252, issued September 9, 1947.

The other end 24 of the lever II is connected by means of a brake pullrod 25 to one end 25 of a live truck brake lever 2l whose other end 223is connected by means of a brake pull rod 29 to one end Sil of a deadtruck brake lever 3| having its other end 32 pivoted to a bracket 33 onthe bolster 'Ihe levers 2l and 3i are connected between their ends atpoints 34 and 35, respectively, and by means of links 3B and 3l,respectively, to the one end 3S and 39 of levers 40 and 4I,respectively. As is best shown in Fig. l, the levers 49 and (il havetheir other ends 42 and 43, respectively, connected to brake beams 44and 45, respectively, having brake shoes 4S and 4l, respectively,disposed inside of, and coacting with, the wheels 2 and I, respectively.Brake shoes 4B and 49 disposed outside of, and coacting with, the wheels2 and i, respectively, are provided on brake beams 50 and 5I,respectively, which are connected to the one ends 52 `and 53,respectively, of levers 54 and 55, respectively, having their other ends55 and 5l, respectively, pivoted to brackets 58 and 69, respectively,projecting from the bolster 'I towards the two ends of the truck. Thelevers 4D and 54 are connected to each other at points intermediatetheir ends by means of a connecting rod 6D, and a similar connecting rodGI interconnects the levers 4I and 55. The brake shoes are suspended byhangers 62 (Fig. l.) from the side members and 5 of the truck frame.Preferably the brake pull rod 29 between the live and dead truck brakelevers 2l and 3| consists of an automatic slack adjuster having anoperating lever 63 (Fig. 2) pivoted between its ends to the lever 21 inthe point 34 and having one end linked to the bolster l by means of alink 64, the mechanism of the slack adjuster to be operated beingconnected to the other end of the operating lever G3. Sliding coverplates 65 and 63 through which the brake pull rods I4 and 25,respectively, project, may be provided for closing the necessaryelongated openings for these rods in the wall of the housing Ill whichis in the form of a chamber formed in the hollow crossbeams or bolster'1.

Obviously, when braking, the brake applying leverage will be determinedby the position of the shiftable iulcrum Il. for the variable leveragelever II. For adjusting this position along the track 23 automaticallyaccording to the load from the car body reposing on the crossbeam orbolster of the swivelling truck, there is a mechanism now to bedescribed. This mechanism is best shown in Fig. 3 and comprises acalibrated spring, preferably in the form of a composite spring composedof two coiled compression springs B'I and 58 of dilerent dimensions,working in parallel and preferably arranged one within the other asshown, which spring 6l, 68 by means of two levers 69 and 'I balancespart of the weight of the bolster 'I and the load thereon reposing onthe supporting springs 8 and 9 at the two sides of the truck. Thebalancing spring 6l, 68 and levers Se and 'l0 are disposed and housed inthe bolster ll. The levers S9 and 'Iii extend within the bolster fromthe ends thereof to the spring 61, 68 which is situated midway betweenthe ends of the bolster and is inserted and acts between a cup-shapedlower supporting member 'Ii closing an insertion opening l2 in thebottom of th-e hollow bolster l and removably attached thereto, and anupper thrust plate 'I3 movable vertically on a central stud 'I4projecting from the bottom of the cup 'II and guiding the surroundingspring 6l, Gil. The Spring thrust plate 7E rosiliently supports theinnery ends of the two levers t9 and lil which a short distance fromtheir outer ends are fulcrumed to the bolster 'i shown at and l5,respectively. At their outer ends the levers 69 and Eil repose onvertically movable thrust plates l'l and I8, respectively, on top of thesupporting springs Il and El, respectively. so that the levers Gil andl@ support the bolsterI l from the supporting springs 8 and S.

It is important to note that the two levers 69, 'iii will compress thebalancing spring 6T, 63 by a force which is derived from the loads onthe supporting springs 5l and S at both sides of the truck and isproportional to the sum of these loads independently of any possiblenonuniform distribution or the weight of the bolster and the car bodycarried thereby on the supporting springs 8 and S at the two sides ofthe truck. Obviously the balancing spring (il, 6B resiliently yields tothis force from the levers 65], IQ, and the yielding movements aretransmitted by a link and lever system to the shiftable ulcrum I2 foradjusting the position thereof according to the load on the truck so asto increase the brake applying leverage of the variable leverage lever II with increasing load on the truck. In the constructional form shownsaid link and lever system comprises a bell crank lever I9 which ispivoted to the bolster l at 8G and has one arm linked by means of a linkill to one of the levers S9, l, and the other arm connected with theshiftable fulcrum I2 by means oi a link rod 82. This rod 82 may includea member 32a capable of yielding to the movements of the lever T9 whenthe fulcrum Il. is blocked against movement during a braking op eration.Preferably the rod E32 also should be adjustable in respect of itslength in order to allow for adjustment of the position of the shiftablefulcrum I2 so as to correspond properly toa given vehicle load.

In the center ol the bolster 7 is provided the center pin 83 (Figs. land 2) about which the truck swivels in relation to the car body carriedthereby. In the constructional form shown the levers "59 and 'lll whoseinner ends extend a little beyond each other, are fork-shaped andstraddle the pin 83.

As will be understood from the foregoing description taken in connectionwith the drawings, the bolster 'l and the variable leverage gear ll, I2as well as the load-control mechanism for the shiftable fulcrum I2,which mechanism com-- prises the balancing spring 61, 68 and levers 69and 'lil and the link and lever system 'lil-82, and possibly also thebrake cylinder I5 (Fig. Zl), may be assembled and then mounted as aconstructional unit in the frame of the truck.

The details or the construction herein shown and described for thepurpose of illustrating the invention may be varied and substituted byequivalents Within wide limits without departing from the spirit of theinvention or the scope of the appendant claims.

What I claim and desire to secure by Letters Patent is:

l. In a variable load brake for a car-truck comprising a wheeled frame,a movable car-supporting bolster carried and guided by said frame,

springs supporting. said bolster from said frame at both sides of thetruck, a hollow crossbeam forming said movable car-supporting bolster, atruck brake rigging on the truck, a variable leverage gear comprising avariable leverage brake lever and a shiftable iulcrum therefor formingparts of said truck brake rigging for varying the brake applyingleverage thereof, leverage gear being housed in and carried by saidmovable car-supporting crossbeam so as to partake in the movementsthereof, other parts of said truck brake rigging being mounted on saidframe, and mechanism mounted and housed in said movable hollow crossbeamfor adjusting the position of said shiftable fulcrum in relation to saidmovable crossbeam automatically according to the load reposing on saidsupporting springs.

2. In a variable load brake for a car-truck comprising a wheeled framehaving two side members, a movable car-supporting bolster extendingtransversely of said frame and carried and guided by said side members,and springs supporting said bolster from said side members, a hollowcrossbeam forming said bolster, a brake rigging including a variableleverage gear comprising a variable leverage brake lever and a shiftablefulcrum therefor, a chamber formed in said hollow crossbeam integrallytherewith and housing said variable leverage gear, a removable coverclosing said chamber at one side of said crossbeam, a brake cylinderattached to said cover, a push rod projecting from said brake cylinderthrough said cover into said chamber and having its projecting endconnected to one end of said variable leverage brake lever, andmechanism for adjusting the position of said shiftable fulcrumautomatically according to the load reposing on said supporting springs,said mechanism being disposed in said hollow crossbeam.

3. In a variable load brake for a car-truck comprising a wheeled frame,a movable car-supporting bolster extending transversely of said frameand having its ends Carried and guided therein, springs supporting saidlbolster from said frame at both sides thereof, a truck brake rigging onthe truck, a track provided on said movable bolster and extendinglongitudinally thereof transversely of said frame, a variable leveragebrake lever, a shiftable fulcrum for said lever, said fulcrum beingshiftable along said track and supported thereby, said variable leveragebrake lever` and said shiftable fulcrum therefor constituting a variableleverage gear carried by and partalring in the movements of said movablebolster forming parts of said truck brake rigging for varying the brakeapplying leverage thereof, other parts of said truck brake rigging beingmounted on said frame, and means for adjusting the position of saidshiftable fulcrum in relation to said movable bolster along said truckthereon automatically according to the load reposing on said supportingsprings.

e. In a variable load brake for a car-truck comprising a wheeled framehaving two side members, a movable car-supporting bolster eX- tendingtransversely of said frame and having its ends carried and guided bysaid side members, springs supporting said movable bolster from saidside members, a hollow crossbeam forming said bolster and providinginside thereof a track extending longitudinally of said crossbeamtransversely of said frame, a variable leverage brake lever and ashiftable fulcrum therefor housed in and carried by said movable hollowcrossbeam so as to partake in the movements thereof, said fulcrum beingshiftable along and supported by said track inside of said hollowcrossbeam, said variable leverage brake lever and said fulcrum thereforforming parts of said truck brake rigging for varying the brake applyingleverage thereof, other parts of said truck brake rigging being mountedon said frame, and mechanism mounted and housed in said movable hollowcrossbeam for adjusting the position of said shiftable fulcrum inrelation to said hollow crossbeam along said track therein automaticallyaccording to the load reposing on said supporting springs.

5. In a variable load brake for a car-truck comprising a wheeled framehaving two Side members, a movable oar-supporting bolster extendingbetween and carried and guided by said side members, and springssupporting said movable bolster from said side members, a brake riggingincluding a variable leverage gear mounted on said movable bolster andcomprising a variable leverage brake lever and a shiftable fulcrumtherefor, and means for adjusting the position of said shiftable fulcrumin relation to said movable bolster automatically according to the loadreposing on said supporting springs, said means comprising a springdisposed at the center of said movable bolster nad supported thereby,and two levers extending longitudinally of said movable bolster andhaving outer ends reposing on said supporting springs and inner endssupported from said movable bolster by said centrally disposed spring,said two levers being fulcrumed to said movable bolster at shortdistances from said outer ends.

6. In a variable load brake for a Car-truck comprising a wheeled framehaving two side members, a movable car-supporting bolster extendingbetween said side members and carried and guided by them, and springssupporting said bolster from said side members, a hollow crossbeamforming said movable bolster, a brake rigging including a variableleverage gear mounted and housed in said hollow crossbeam and comprisinga variable leverage brake lever and a shiftable fulcrum therefor, andmeans for adjusting the position of said shiftable fulcrum automaticallyaccording to the load reposing on said supporting springs, said meanscomprising a spring disposed centrally in said hollow crossbeam, twolevers disposed in said hollow crossbeam and having outer ends reposingon said supporting springs and inner ends supported by said -centrallydisposed spring, said two levers being fulcrumed to said crossbeam atshort distances from said outer ends, and a link and lever system fortransmitn ting yielding movements of said centrally disposed spring tosaid shiftable fulcrum for the adjustment thereof.

'7. In a variable load brake for a car-truck as claimed in claim 6, theadditional feature that said hollow crossbeam has a center pin to swivelabout in relation to the body of the car, and that said inner ends ofsaid two levers supported by said centrally disposed spring projectbeyond each other and are fork-shaped and straddle said center pin.

8. In a variable load brake as claimed in claim G, the additionalfeature that said centrally disposed spring is a compression springinserted and acting between a cup-shaped member closing an insertionopening in the bottom of said hollow crossbeam, and a thrust plate whichsupports said inner ends of said two levers and is vertically movable ona central stud projecting from the bottom of said cup-shaped member and`guiding 7 8 ghrust plate and said centrally disposed REFERENCES CITED9. Irl a variable load brake as claimed in claim The OHOWITS refelellesare 0f ISCOId in the 6, the additional feature that said link and leverle Of this patenti system comprises a bell Crank lever pivotally 5UNITED STATES PATENTS mounted in said hollow crossbeam, a linkconnecting one arm of said bell crank lever to the Number Name Dai@inner end of one of .said two levers supported 1,002,312 Ransom Sept- 5,1911 by said centrally disposed spring, and a, link rod 2,367,586 KelleyJal- 16, 1945 connecting said shiftable fulcrum to the other 102,394,038 BI'OWan Feb- 5, 1945 arm of said bell crank lever.

AXEL GEORG HJALMAR CARLBOM.

